Conversely, the mutation frequency of other cancer driver genes or gene modules (such as TP53, PIK3CA, ARID1A, and BRAF) was not significantly different between the two groups (q > 0.05) or had a slightly higher mutation frequency in primary cancer than in metastatic cancer samples (Supplementary Table S1–6). Here, PIK3CA is linked to metastatic malignant neoplasm.